A polyimide anode with high capacity and superior cyclability for aqueous Na-ion batteries

A redox-active and water-insoluble polyimide, poly-(naphthalene four formyl ethylenediamine), demonstrates a high capacity of 130 mA h g(-1), a strong rate capability at 10 C rate and an excellent capacity retention of 91.2% over 1000 cycles, offering a low cost and environmentally benign anode for aqueous Na-ion batteries.